Google's so removed two Chrome browser extensions over the weekend, because the software appears to serve spam ads—in turn violating company's terms of service.

Both the "Add to Feedly" and "Tweet This Page" extensions were quietly updated recently but in the process began feeding users undesirable ads, reports the Wall Street Journal. In fact, the situation seemed so bad that reviews on the "Add to Feedly" extension page referred to the software as spam.

Google's policy, updated in December, allows extensions to only insert adverts on one part of a web page. "Add to Feedly" and "Tweet This Page" seem to have been injecting multiple ads, including in places where they never appear, like Google's home page.

It's a result of the fact that Google doesn't vet extension code before it's updated by authors on its server, and allows new versions to pushed automatically to the computers of users. So, when Amit Agrawal, the developer of "Add to Feedly," admitted that he'd sold his extension to an unknown buyer, it should perhaps not have been surprising that said purchaser also injected invasive advertising into the code. A similar thing happened to Tweet This Page.

Each extension had fewer than 100,000 users at the time, and both have now been removed by Google. Let's just hope it doesn't become a common trend. [WSJ]